DesignerDataSourceView 类
定义
重要
一些信息与预发行产品相关,相应产品在发行之前可能会进行重大修改。 对于此处提供的信息,Microsoft 不作任何明示或暗示的担保。
用作设计时数据源视图类的基类。
public ref class DesignerDataSourceView abstract
public abstract class DesignerDataSourceView
type DesignerDataSourceView = class
Public MustInherit Class DesignerDataSourceView
- 继承
-
DesignerDataSourceView
- 派生
示例
下面的代码示例演示如何创建自定义 DesignerDataSourceView 对象以及一个自定义 IDataSourceViewSchema 类和两个自定义 IDataSourceFieldSchema 类。
此示例是 类的较大示例的 DataSourceDesigner 一部分。
// A design-time data source view
public class CustomDesignDataSourceView : DesignerDataSourceView
{
private ArrayList _data = null;
public CustomDesignDataSourceView(
CustomDataSourceDesigner owner, string viewName)
: base(owner, viewName)
{}
// Get data for design-time display
public override IEnumerable GetDesignTimeData(
int minimumRows, out bool isSampleData)
{
if (_data == null)
{
// Create a set of design-time fake data
_data = new ArrayList();
for (int i = 1; i <= minimumRows; i++)
{
_data.Add(new BookItem("ID_" + i.ToString(),
"Design-Time Title 0" + i.ToString()));
}
}
isSampleData = true;
return _data as IEnumerable;
}
public override IDataSourceViewSchema Schema
{
get { return new BookListViewSchema(); }
}
// Allow getting the record count
public override bool CanRetrieveTotalRowCount
{
get { return true; }
}
// Do not allow deletions
public override bool CanDelete
{
get { return false; }
}
// Do not allow insertions
public override bool CanInsert
{
get { return false; }
}
// Do not allow updates
public override bool CanUpdate
{
get { return false; }
}
// Do not allow paging
public override bool CanPage
{
get { return false; }
}
// Do not allow sorting
public override bool CanSort
{
get { return false; }
}
}
' A design-time data source view
Public Class CustomDesignDataSourceView
Inherits DesignerDataSourceView
Private _data As ArrayList = Nothing
Public Sub New(ByVal owner As CustomDataSourceDesigner, ByVal viewName As String)
MyBase.New(owner, viewName)
End Sub
' Get data for design-time display
Public Overrides Function GetDesignTimeData( _
ByVal minimumRows As Integer, _
ByRef isSampleData As Boolean) As IEnumerable
If IsNothing(_data) Then
' Create a set of design-time fake data
_data = New ArrayList()
Dim i As Integer
For i = 1 To minimumRows
_data.Add(New BookItem("ID_" & i.ToString(), _
"Design-Time Title 0" & i.ToString()))
Next
End If
isSampleData = True
Return CType(_data, IEnumerable)
End Function
Public Overrides ReadOnly Property Schema() As IDataSourceViewSchema
Get
Return New BookListViewSchema()
End Get
End Property
' Allow getting the record count
Public Overrides ReadOnly Property CanRetrieveTotalRowCount() As Boolean
Get
Return True
End Get
End Property
' Do not allow deletions
Public Overrides ReadOnly Property CanDelete() As Boolean
Get
Return False
End Get
End Property
' Do not allow insertions
Public Overrides ReadOnly Property CanInsert() As Boolean
Get
Return False
End Get
End Property
' Do not allow updates
Public Overrides ReadOnly Property CanUpdate() As Boolean
Get
Return False
End Get
End Property
' Do not allow paging
Public Overrides ReadOnly Property CanPage() As Boolean
Get
Return False
End Get
End Property
' Do not allow sorting
Public Overrides ReadOnly Property CanSort() As Boolean
Get
Return False
End Get
End Property
End Class
// A custom View Schema class
public class BookListViewSchema : IDataSourceViewSchema
{
public BookListViewSchema()
{ }
// The name of this View Schema
public string Name
{
get { return "BookList"; }
}
// Build a Field Schema array
public IDataSourceFieldSchema[] GetFields()
{
IDataSourceFieldSchema[] fields = new IDataSourceFieldSchema[2];
fields[0] = new CustomIDFieldSchema();
fields[1] = new CustomTitleFieldSchema();
return fields;
}
// There are no child views, so return null
public IDataSourceViewSchema[] GetChildren()
{
return null;
}
}
// A custom Field Schema class for ID
public class CustomIDFieldSchema : IDataSourceFieldSchema
{
public CustomIDFieldSchema()
{ }
// Name is ID
public string Name
{
get { return "ID"; }
}
// Data type is string
public Type DataType
{
get { return typeof(string); }
}
// This is not an Identity field
public bool Identity
{
get { return false; }
}
// This field is read only
public bool IsReadOnly
{
get { return true; }
}
// This field is unique
public bool IsUnique
{
get { return true; }
}
// This field can't be longer than 20
public int Length
{
get { return 20; }
}
// This field can't be null
public bool Nullable
{
get { return false; }
}
// This is a Primary Key
public bool PrimaryKey
{
get { return true; }
}
// These properties do not apply
public int Precision
{
get { return -1; }
}
public int Scale
{
get { return -1; }
}
}
// A custom Field Schema class for Title
public class CustomTitleFieldSchema : IDataSourceFieldSchema
{
public CustomTitleFieldSchema()
{ }
// Name is Title
public string Name
{
get { return "Title"; }
}
// Type is string
public Type DataType
{
get { return typeof(string); }
}
// This is not an Identity field
public bool Identity
{
get { return false; }
}
// This field is not read only
public bool IsReadOnly
{
get { return false; }
}
// This field is not unique
public bool IsUnique
{
get { return false; }
}
// This field can't be longer than 100
public int Length
{
get { return 100; }
}
// This field can't be null
public bool Nullable
{
get { return false; }
}
// This is not the Primary Key
public bool PrimaryKey
{
get { return false; }
}
// These properties do not apply
public int Precision
{
get { return -1; }
}
public int Scale
{
get { return -1; }
}
}
' A custom View Schema class
Public Class BookListViewSchema
Implements IDataSourceViewSchema
Public Sub New()
End Sub
' The name of this View Schema
Public ReadOnly Property Name() As String Implements IDataSourceViewSchema.Name
Get
Return "BookList"
End Get
End Property
' Build a Field Schema array
Public Function GetFields() As IDataSourceFieldSchema() Implements IDataSourceViewSchema.GetFields
Dim fields(1) As IDataSourceFieldSchema
fields(0) = New CustomIDFieldSchema()
fields(1) = New CustomTitleFieldSchema()
Return fields
End Function
' There are no child views, so return Nothing
Public Function GetChildren() As IDataSourceViewSchema() Implements IDataSourceViewSchema.GetChildren
Return Nothing
End Function
End Class
' A custom Field Schema class for ID
Public Class CustomIDFieldSchema
Implements IDataSourceFieldSchema
Public Sub New()
End Sub
' Name is ID
Public ReadOnly Property Name() As String Implements IDataSourceFieldSchema.Name
Get
Return "ID"
End Get
End Property
' Data type is string
Public ReadOnly Property DataType() As Type Implements IDataSourceFieldSchema.DataType
Get
Return GetType(String)
End Get
End Property
' This is not an Identity field
Public ReadOnly Property Identity() As Boolean Implements IDataSourceFieldSchema.Identity
Get
Return False
End Get
End Property
' This field is read only
Public ReadOnly Property IsReadOnly() As Boolean Implements IDataSourceFieldSchema.IsReadOnly
Get
Return True
End Get
End Property
' This field is unique
Public ReadOnly Property IsUnique() As Boolean Implements IDataSourceFieldSchema.IsUnique
Get
Return True
End Get
End Property
' This field can't be longer than 20
Public ReadOnly Property Length() As Integer Implements IDataSourceFieldSchema.Length
Get
Return 20
End Get
End Property
' This field can't be null
Public ReadOnly Property Nullable() As Boolean Implements IDataSourceFieldSchema.Nullable
Get
Return False
End Get
End Property
' This is a Primary Key
Public ReadOnly Property PrimaryKey() As Boolean Implements IDataSourceFieldSchema.PrimaryKey
Get
Return True
End Get
End Property
' These properties do not apply
Public ReadOnly Property Precision() As Integer Implements IDataSourceFieldSchema.Precision
Get
Return -1
End Get
End Property
Public ReadOnly Property Scale() As Integer Implements IDataSourceFieldSchema.Scale
Get
Return -1
End Get
End Property
End Class
' A custom Field Schema class for Title
Public Class CustomTitleFieldSchema
Implements IDataSourceFieldSchema
Public Sub New()
End Sub
' Name is Title
Public ReadOnly Property Name() As String Implements IDataSourceFieldSchema.Name
Get
Return "Title"
End Get
End Property
' Type is string
Public ReadOnly Property DataType() As Type Implements IDataSourceFieldSchema.DataType
Get
Return GetType(String)
End Get
End Property
' This is not an Identity field
Public ReadOnly Property Identity() As Boolean Implements IDataSourceFieldSchema.Identity
Get
Return False
End Get
End Property
' This field is not read only
Public ReadOnly Property IsReadOnly() As Boolean Implements IDataSourceFieldSchema.IsReadOnly
Get
Return False
End Get
End Property
' This field is not unique
Public ReadOnly Property IsUnique() As Boolean Implements IDataSourceFieldSchema.IsUnique
Get
Return False
End Get
End Property
' This field can't be longer than 100
Public ReadOnly Property Length() As Integer Implements IDataSourceFieldSchema.Length
Get
Return 100
End Get
End Property
' This field can't be null
Public ReadOnly Property Nullable() As Boolean Implements IDataSourceFieldSchema.Nullable
Get
Return False
End Get
End Property
' This is not the Primary Key
Public ReadOnly Property PrimaryKey() As Boolean Implements IDataSourceFieldSchema.PrimaryKey
Get
Return False
End Get
End Property
' These properties do not apply
Public ReadOnly Property Precision() As Integer Implements IDataSourceFieldSchema.Precision
Get
Return -1
End Get
End Property
Public ReadOnly Property Scale() As Integer Implements IDataSourceFieldSchema.Scale
Get
Return -1
End Get
End Property
End Class
实施者说明
从 DesignerDataSourceView 类继承时,必须重写 GetDesignTimeData(Int32, Boolean) 方法,以创建符合 Schema 属性的示例数据,或从数据源返回实际数据。
构造函数
DesignerDataSourceView(IDataSourceDesigner, String) |
使用指定的数据源设计器和视图名称初始化 DesignerDataSourceView 类的新实例。 |
属性
CanDelete |
获取一个值,该值指示与当前 DataSourceControl 对象相关联的 DataSourceView 对象是否支持 ExecuteDelete(IDictionary, IDictionary) 方法。 |
CanInsert |
获取一个值,该值指示与当前 DataSourceControl 对象相关联的 DataSourceView 对象是否支持 ExecuteInsert(IDictionary) 方法。 |
CanPage |
获取一个值,该值指示与当前 DataSourceControl 对象关联的 DataSourceView 对象是否支持对由 ExecuteSelect(DataSourceSelectArguments) 方法检索到的数据进行分页。 |
CanRetrieveTotalRowCount |
获取一个值,该值指示与当前 DataSourceControl 对象关联的 DataSourceView 对象是否支持检索数据的总行数,而不是检索数据本身。 |
CanSort |
获取一个值,该值指示与当前 DataSourceControl 对象关联的 DataSourceView 对象是否支持基础数据源的排序视图。 |
CanUpdate |
获取一个值,该值指示与当前 DataSourceControl 对象相关联的 DataSourceView 对象是否支持 ExecuteUpdate(IDictionary, IDictionary, IDictionary) 方法。 |
DataSourceDesigner |
获取对创建此 DesignerDataSourceView 控件的设计器的引用。 |
Name |
获取在创建 DesignerDataSourceView 类的此实例时提供的视图的名称。 |
Schema |
获取一个架构,该架构描述此视图对象所表示的数据源视图。 |
方法
Equals(Object) |
确定指定对象是否等于当前对象。 (继承自 Object) |
GetDesignTimeData(Int32, Boolean) |
使用指定的行数生成与关联数据源控件的架构相匹配的设计时数据,以指示其返回示例数据还是实时数据。 |
GetHashCode() |
作为默认哈希函数。 (继承自 Object) |
GetType() |
获取当前实例的 Type。 (继承自 Object) |
MemberwiseClone() |
创建当前 Object 的浅表副本。 (继承自 Object) |
ToString() |
返回表示当前对象的字符串。 (继承自 Object) |